Abstract:
Polypropylene (PI'}-titanium dloxidc (Ti02) composites with difterent wcight ratio
ofPP and Ti02 were prepared by extruSIOn moulding technique, XRD, OTAI TGA
and lR spectroscopy wcre performed for structural analysis of the I'P and
composites. The UV-Visible absorption spectroscopy, I-V and I-T measurements
on PI' and composites were performed to understand the optical and electrical
behaviour ofthe matenals
The XRD study indicates the presence of defects between the crystallites in fibrils
and I or imperfection in the ordered phase ofPP. TiO) is found to be diffused into
the crystalline rcgion of PP. A decrease in the crystallite sin: is consistent with a
decrease of fractlOnal crystallinity of the composites with thc increasc of -ri02
contcnt. No ncw 1R absorption band appcars due to the inclusion of Ti02 in PP
CH) and C-C groups remain unchangcd where (lnly C-H bond ISaffected due to the
inclusion of Ti02 in PP, In the DTAffGA investigation all the composite samples
show a melting temperature of 430 K .The changc of exothenn temperatures
indicates a structural modification in the PP owing to inclusion of Ti02. SPT-l is
found to hc themJa\1y most stahle.
In the UV-VIS absorption it is found that the band gap of composites is less than
that of PP . Indirect transition energy gap, in sample SPT-l to 4, suggests the
presence of two-step transition process in composites. IndIrect energy gap increases
and direct energy gap decreases with the increasing percentage ofTi02 in PP, From
the I-V characteristics Ohmic region is (lbserved in high v(lltage region hut at low
voltage region thenniomc effect ISobserved giving risc to nonunifonnity of the field
distribution between the electrode and samples. The l-T characteristics show the
sharp increase of conductivity at high temperature and the eXistence of shallow trap
levels Thermally activated hopping eonductlon of ions between localized state is
tbund to be operative III thl; matenals,
